For example, in an electrical storage device including a stacking type electrode assembly such as a lithium ion rechargeable battery, as a method of stacking electrodes, a pick and place (P&P) method that uses a robot provided with a suction unit is frequently used. As one of a method of improving productivity in a manufacturing line of the electrical storage device, speeding-up of the manufacturing line is considered. To realize the speeding-up, for example, it is necessary to raise an electrode supply speed (stacking speed) to a stacking section in a stacking process. However, in the case of stacking electrodes on the stacking section by using the robot, for example, it is necessary to follow a negative pressure control of a suction unit, and the like, and thus it is difficult to raise the electrode stacking speed. As a result, this situation becomes an obstacle to the speeding-up of the manufacturing line. In contrast, as an electrode stacking device capable of realizing high-speed stacking, for example, there is known a device that is disclosed in Patent Literature 1 and Patent Literature 2.
The electrode stacking device disclosed in Patent Literature 1 includes two supply mechanisms which respectively supply a positive electrode and a negative electrode, two drop movement units which are disposed on a lower side of the supply mechanism to be perpendicular to each other and drop and move the positive electrode and the negative electrode, which are respectively supplied from the supply mechanisms, to a predetermined position by using the gravity, and a guide stacking unit that is disposed on a lower side of the drop movement units, and sequentially guides the positive electrode and the negative electrode which are respectively ejected from ejection sections of the drop movement units to a predetermined position and stacks the electrodes. The guide stacking unit includes a bottom wall on which a stacked body is placed, and two erected walls which are provided to protrude in a direction perpendicular to the bottom wall, and stops movement of the electrodes ejected from the ejection sections of the drop movement units and positions the electrodes. When stacking the positive electrode and the negative electrode, the positive electrode is supplied in a direction that faces one of the erected walls, and the negative electrode is supplied in a direction that faces the other electrode wall. A positive electrode and a negative electrode which are supplied to the guide stacking unit are dropped on the bottom wall or the positive electrode and the negative electrode which have been stacked, and are stopped after collision with the erected walls.
In the supply mechanism disclosed in Patent Literature 1, a positive electrode or a negative electrode, which is cut out from a strip-shaped positive electrode material or negative electrode material, is directly dropped on the drop movement unit. In a typical stacking type electrode, a tab, which serves as a current passage with an external terminal, has a shape that protrudes from a rectangular electrode main body. Accordingly, in the case of applying the supply mechanism to the electrode including the tab, the following configuration is considered. That is, in a manufacturing line, an electrode in which a separate tab is joined to the electrode main body, or an electrode in which a tab shape is integrally formed through a plurality of times of cutting is conveyed by a conveying device such as a conveyor, and is dropped onto the drop movement unit.
The electrode stacking device described in Patent Literature 2 includes three supply sections which are disposed on a stand and respectively supply a positive electrode, a negative electrode, and a separator, three pairs of rollers which respectively nip and convey the positive electrode, the negative electrode, and the separator which are respectively supplied from the supply sections, a stacking section which is disposed on a downstream side in a conveying direction of the pairs of rollers and in which the positive electrode, the negative electrode, and the separator which are respectively conveyed from the pairs of rollers are stacked, and a regulation unit that is disposed on an end of the stacking section and regulates a position of the positive electrode, the negative electrode, and the separator which are conveyed from the respective pairs of rollers.
In addition, in the case of speeding up the production line, the following method is also known. Specifically, only processes or a plurality of kinds of processing in which time-shortening is difficult are parallelized. For example, in a piling device described in Patent Literature 3, cut-out materials are classified by four branched conveyors arranged above and below, and the classified cut-out materials are decelerated on deceleration conveyors and are stacked in a piling chamber that is partitioned into four stages.